In underground mining operations it is usually necessary for the roof to be bolted at spaced intervals along the tunnel or gallery, which bolting can be performed in a number of different ways. In recent years mining operators have been looking for ways of performing this function more efficiently and more economically than has been previously possible. In this regard the provision of apparatus which simplifies the function to a point where the skill of the operator is reduced dramatically is a distinct economic advantage.
The present invention provides such a simplified means of bolting the roof of a tunnel without the need for highly sophisticated equipment or even a high degree of skill on the part of the operator and, as such, is a distinct improvement over the present apparatus.
One of the prior art apparatuses comprises a framework which is mounted in a vertical position on the floor of the tunnel and has a pair of hydraulic rams and a chain which is positioned between the vertical legs of the frame in an M-like configuration with its ends connected respectively to the hydraulic rams. The roof bolt to be injected is positioned on the chain at approximately the centre thereof which forms the centre leg of the M. The hydraulic rams are then extended to draw downwardly the outer legs of the M thereby forcing upwardly the centre leg thereof, such that the roof bolt will be forced into the roof.
One of the problems with this type of apparatus is that the chain is inclined to fracture thereby placing the operator and anybody nearby at great risk during injection of the bolt.